Hydropneumatic device



R- LIEEBAU. HYDROPNEUMATIC DEVICE. APPLICATION FILED SEPT. 1a, 1915.RENEWED ran. 19, 1920.

Patented May 18, 1920.

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lAjVE/VT K M Q:- \4 -Q HIS ATTORNEY IN FACT WITN.E I

. plications and patent, has the principle of resilient support by anelasadapted for use as RICHARD LIEIBAU, OF NEW HAVEN, CONNECTICUT,

ASSIGNOR TO mnwnsrmenousa AIR SPRING COMPANY, A CORPORATION OFPENNSYLVANIA.

nYnnorzmnmarrc DEVICE.

Specification of Letters Patent. Patented May 18, 1920.

Application filed September 18, 1915, Serial No. 51,472. RenewedFebruary 19, 1920. Serial No. 359,854.

To all whom it may camera:

Be it known that I, RICHARD LIEBAU, a citizen of the United States, anda resident of New Haven, in the county of New Haven and State ofConnecticut, have made a new and useful Invention in Hydro'pneumaticDevices, of which the following is a specification. y

This invention relates'to hydropneumatic devices of the type set forthinseveral applications for patents filed by me and in Letters Patent- No.1,036,043, issued to George Westinghouse on August 20, 1912.

In the present application, as in the former applications and patent,the invention 7 is embodied in a fluid-compression device a compressionspring broadly applicable in any relation where two bodies are soassociated that resilient support of one is desirable,

and the general object in view in this, as in said former apbeen toembody tic compression medium-such as air, or gas in a commerciallypractical, self-contained, air-tight compression device adapted to serveall of the purposes and functions of a spring.

My present invention also resembles that of the said former applicationsand patent in so far as a fluid-tight-joint between the sliding surfacesof the device is maintained by means of a liquid bath.-

According to the present invention, which is broadly applicable for useas a spring for motor vehicles such as automobiles, (and whichhereinafter without any idea of limiting the invention will be referredto as an air spring), means are provided for forcing air into thecompression chamber of the spring, for automatically determining thenormal of operative relative positions ofthe relatively movable membersof the spring irrespective of the load carried thereby and fortransferring the sealing liquid forming .the bath for the sliding jointfrom a collecting chamber on the low pressure side of the sliding jointto the compression chamber.

The drawing is a sectional elevation of an air spring embodying thisinvention. .In the device the cushion or compression chamber is made upof a cylinder 2, provided with a head 3, .formed i'n'te rally therewithand which telescopes wit in a packing by I presses against'anintermediate sliding and cylinder 4, having a bottom 5 threadedthereinto. Secured to head 3 at 6 is an outer cylinder 7 which serves asa cover or dmud or dust guard and a guide for cylin- Threaded to thelower end of cylinder 2 is a. plunger head 8, which carries a cupleather sliding A seat 10 is formed for packing, said seat the lower endof the-plungei:-"- head andwhich is provided with an upright extension12 which clamps the cup leather to its seatlO.

oint between the cylinders 2 and 4".

A cone expander ring 13 is pressed against the inner depending 11p ofthe cup leather means of a spring '14, which centering member 15,interposed between the cone expander ring and the spring. This member 15slides on the extension of the..

' tow 3 nut 11 and allows the expander rin mova'bly center on thedepending lip o the cup leather packing.v

A spring-backed leather wiperring 17 bears against the inner surface ofcylinder 4 and serves to retain oil or other sealing liquid in thechamber which contains the cup leather packin The depending fl ange ofthe cup leather packing bears against the inner surface of cylinder 4and the chamber containing the packing is in open communication bymeansof a duct 17" with one of the passages 18. These passages-'18,shown by dotted lines, are formed in the plunger head and extendtherethrough, from the space 19 above the plunger head to the space 20below the same and serve as transfer passages for the liquid within thecompression chamber during the compression and extension movements of.the air spring.

At its center the plunger 'head is rovided with a tubular extension 21whic is threaded into the plunger head at 22, and which serves as a pumpcylinder for plunger 23. This pumpcylinder is bored out so as to provideplunger chambers 24 and 2550f different diameters.

The pump plunger 23 having two diameters 28 and 29, snugly fits withinthe bores of the ump cylin er and the portion of larger diameter acts asthe plunger of an air pump for drawing air from the atmosphere chamberof the spring through charging and forcing it into the compressionchamplug 52. ber of the spring, while the portion of The plunger head isdrilled through from smaller diameter serves as the plunger of an top tobottom between two of the through oil pump for transferring oil fromcollecting channels 18 to form a guide passage 53 for achamber on thelow pressure side of pilot valve. This pilot valve consists of a cupleather packing to the compression plunger 54, which engages the same T'slot chamber on the high pressure side of the as the bottom 38 of theoil and air pump cup leather packing. plunger, and the pilot valve isadapted to The le ing chamber 30 formed n the regulate the normal oroperative positions l pressure Side Of the p leather pa k g of therelatively movable members irrespeccollects the oil which passes thepacking and tive of the load to which the spring is subdelivers itthrough check valve 31 to oil jected, pump chamber 32 through passagesand The plunger 5a of the pilot valve is re- 34:. and from the pumpchamber it 13 fOl'CGCl luced {it its upper and as ghgwn at 55, and

I chamber.

through check valve 35 to the compressien is provided with a centralopening or chan so chamber through passages 36 and 7. nel 56, whichplaces the compression cham- Plunger 23 carries a bottom memb r herthrough a restricted orifice 57 in comwhich slidably fits within a Tgroove or slot uni ti with an annular groove 58 formed in the bottommember 5 and th formed-on the larger portion of the plunger plunger ispositively moved during the com- 54. This annular groove is adapted attimes pression and extension movements of the to register with a port 59which lead from spring. the collecting chamber 30 to the bore for Uponthe compression movements of the plunger 54. air spring a partial vacuumwill be created If the air spring has accumulated a presin the oil pumpchamber and when the port sure within the compression chamber by: 34 ispassed bythe lower end of the larger an of the-air p mp suificient tocarry'a portion of plunger 23, the oil from the colcertain load and thisload is removed, the lecting chamber 30 will be drawn into the springwill extend, and if'th'e extension is pump chamber, from which upon h eXeH- sufiicient, annular chamber 58 will register sion movements of thespring, it will be with channel 59 and sufficient pressure will forcedthrough check valve 35. be relieved through the pilot valve to bringDuring the compression and eX'teIISiOII the relatively movable member tonormal or movements of the spring so long as-the top operative position.The restricted orifice 57 of plunger 23 does not pass below port 39 inis provided so that when the spring is workthe pump cylinder, the-airpump will be efing its full range (for instance when the fective fordrawing in air through strainer hi le on hich it i used is traveling 40,check valve 4:1 an P s g end w over rou'gh roads) the occasionalregister of discharge the same through check valve 44: groove 58 ith t59 ill not; e ult in too and passage L5 to the compression chamber greata l of re ur of the air spring. Having described what I now believe to ui g th compres i n and extension be the preferred embodiment of myinvenmovements of the ail sp ing Wh t 1 tion, I desire it to beunderstood that the deof the air pump plunger operates below the viceshown is only illustrative, and that P r th il pump Will he inefieetiveand various changes, modifications, additions air Wi be m r y v inthrough this and omissions may be made in the apparatus port from thecompression chamber of the ill t t d, ith t d ting from the spring andforced out into said compression i it d scope f my inv ntion, as setforth by the appended claims.

Threaded within a central depending boss I What I claim is: c 46 of head3 is a plug 417. This plug is con- 1. In a telescopic air spring havinga slidcentric with tubular e. tension 21 of the ing joint adapted to besealed with liquid, plunger head and is packed against leakage aollector on the low pressure side of'said gy means of soft packings 48,49 and 50. joint for leaked liquid, a pump within the he outercylindrical surface" of the plug is ing f r ch rging the same with air,and provided with an annular groove 51, which a. bleeder de ice forexhausting air from registers with air channel 45. said spring to saidcollector; the operation A filling plug 52- is threaded into the side ofsaid bleeder device being dependent upon of head 3 and is adapted to beprovided with the relative positions of the telescoping an air valve,such as an ordinary tire valve, members.

whereb the requisite amount of air may be 2. An air spring comprisingtelescopindg pumpe into the compression chamber of members, forming achamber having a sli the spring before starting. The sealing lic ingjoint, a paclnng for said joint, 9. pump uid may be introduced intoth'ecompression within the spring for charging said chamber with air underpressure, and a bleeder device for discharging air from said chamber tothe members forming a cushion chamber and low pressure side of saidpacking, the op-' eration of said bleeder device being dependent uponthe relative positions of said members and independent of the load onthe spring or the pressure within said chamber.

3. 11 air spring comprising telescoping members formlng a chamber, apacking for the joint between said members, a pump within the springforcharging said chamber with air, means independent of the load carriedby the spring for rendering said pump at times ineffective as a pump,and a having a sliding joint adapted to be sealed with liquid, removingliquid from said joint and transferring'lt to the cushion chamber,asecond pump within the spring for charging said chamber with air, and ableeder device independent of said pumps for automatically dischargingair from said chamber.

6. In an, air spring, relatively movable nected with'said slidinglecting chamber, a second liquid from said a pump within the spring for.

members forming an extensible cushion chamber having a sliding joint, apump Within the spring for charging said cham= ber with air underpressure, a, second pump within said spring adapted to discharge intosaid chamber and having its intake conjoint, and a bleeder device theoperation 0 which is dependent upon the relative positions of saidmembers for ezghausting air from said chamber.

7. ln an air spring, members forming an extensible cushion chamberhaving a sli joint, a collecting chamber connecting with said slidingjoint, a pump arranged to discharge into said cushionchambenand havingits intake in connection with said colair into said cushion chamber, anda bleeder device dependent upon the relative positions of said membersfor automatically bleedin air from said cushion chamber to said cole'ctin chamber.

8. fii an air spring, members formin an extensible cushion chamberhaving a sliding pump for forcing joint, a pump for automaticallyremoving joint and returning it to said chamber, a second pump withinsaid spring for forcing air into said chamber, said secondpumpconstructed to become inoperative upon extension of said springbeyond a determined point, and a bleeder device within said spring forautomatically discharging air from said chamber.

In testimony whereof, I have hereunto subscribed my name'this 16th dayof Sep tember, 1915. 1

RICHARD LIEBAU.

